The present invention relates to a diamond saw blade used to cut abrasive material like concrete or asphalt, and more specifically to a diamond saw blade which is made by attaching improved undercut preventing tips, produced by diffusing and joining cobalt-based powder onto cemented carbide tips including tungsten carbide powder at a high temperature, to each of shank slot walls formed on the circumference of a diamond saw blade by means of laser welding.
A conventional diamond saw blade 10 for cutting abrasive material as mentioned above comprises, as shown in FIG. 3, plural tips 14 attached to the circumference of a shank 12 at a finite interval and slots 12a for discharging cut chips, the slots being positioned between the adjoining two diamond tips 14.
These slots and diamond cutting tips were, in a negative manner, subjected to the chip powder or scraps generated at the material being cut during cutting operation. In other words, the shavings, powder or scraps produced from asphalt, concrete or the like during a rotary cutting operation tend to erode the area of slots 12a as they move at high speed toward the circumference of a shank due to centrifugal force, resulting in undercut phenomena.
As the result of these undercut phenomena, the contact area of the diamond tips with the shank 12 is first eroded or cracked and subsequently a breakage state can follow or even diamond tips 14 can fall off the shank 12.
Accordingly, diamond tips come to fail in conducting their function owing to the undercut phenomena, before their life is over. As the result, the life of the diamond saw blade is in turn shortened, causing the problem of imperfect performance in cutting work.
In an effort to resolve such a conventional problem in connection with undercut effect, the wedge segment designed to position lower than normal was proposed for the diamond chip and there was also another proposal that only cemented carbide tips be provided to chip discharging slot walls in a steel core.
In the case of the wedge segment, the machining process for a shank is complex and the wedge segment requires more material than its ordinary counterpart, resulting in increased production cost. In the case of using the cemented carbide tips, the need for manual joining work by using silver-lead causes the decrease in productivity. Particularly, for the case of using the tip on semi-dry basis, there may be some risk because cemented carbide tips including tungsten carbide powder can fall off during a cutting operation due to the weak welding from thermal instability.
The present invention is intended to resolve the above-described problems with the conventional art and so the object of the invention is to provide a diamond saw blade which is made by attaching undercut preventing tips, produced by diffusing and joining cobalt-based powder to cemented carbide tips at a high temperature, to respective shank slot walls formed on the circumference of a diamond saw blade by means of laser welding.
The object as described above is achieved according to an aspect of the invention by a diamond saw blade with a shank, and with plural diamond tips provided on the circumference of the shank at a finite interval, slots for discharging cut chips being positioned between the adjoining diamond tips, further comprising undercut preventing tips disposed on respective walls of said slots, said undercut preventing tips including tungsten-carbide-based ultra hard tips provided with cobalt-based layer, wherein said undercut preventing tips are formed by diffusing and joining the cobalt-based powder to said ultra hard tips at a high temperature and said undercut preventing tips are fixed on respective walls of said slots by means of laser welding.